U.S. patent number 4,435,628 [Application Number 06/029,227] was granted by the patent office on 1984-03-06 for seed heating microwave appliance.
This patent grant is currently assigned to Raytheon Company. Invention is credited to Robert F. Bowen, E. Eugene Eves, II, George Freedman, Thomas J. Martel, Wesley W. Teich.
United States Patent |
4,435,628 |
Bowen , et al. |
* March 6, 1984 |
Seed heating microwave appliance
Abstract
An appliance for heating seeds, nuts, grains and the like such
as popcorn kernels, for example, by means of microwave radiation,
comprising a bowl which is transparent to microwave energy and
which has in its lower region an area of restricted size for
holding unheated seeds in a clump, the area of the bowl above the
restricted area being larger to allow heated seeds to expand, and
means for directing the microwave energy upon the clump of
seeds.
Inventors: |
Bowen; Robert F. (Burlington,
MA), Freedman; George (Wayland, MA), Teich; Wesley W.
(Wayland, MA), Martel; Thomas J. (North Reading, MA),
Eves, II; E. Eugene (Nabnasset, MA) |
Assignee: |
Raytheon Company (Lexington,
MA)
|
[*] Notice: |
The portion of the term of this patent
subsequent to June 19, 1996 has been disclaimed. |
Family
ID: |
26704701 |
Appl.
No.: |
06/029,227 |
Filed: |
April 11, 1979 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
865824 |
Dec 30, 1977 |
4158760 |
Jun 19, 1979 |
|
|
Current U.S.
Class: |
219/734; 219/732;
426/243; 99/323.5; 99/DIG.14; D7/325 |
Current CPC
Class: |
A47J
36/027 (20130101); A23L 7/187 (20160801); Y10S
99/14 (20130101) |
Current International
Class: |
A23L
1/18 (20060101); A47J 36/02 (20060101); H05B
006/80 () |
Field of
Search: |
;219/1.55E,1.55F,1.55R,432 ;99/323.4,323.5,323.8,451,345,DIG.14,347
;426/107,113,241,243,449 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Reynolds; B. A.
Assistant Examiner: Leung; Philip H.
Attorney, Agent or Firm: Clark; William R. Pannone; Joseph
D. Meaney; John T.
Parent Case Text
This is a division of application Ser. No. 865,824, filed Dec. 30,
1977, now U.S. Pat. No. 4,158,760 issued June 19, 1979.
Claims
What is claimed is:
1. The method of popping kernels using microwave energy, comprising
the steps of:
bunching said kernels together in a clump;
radiating said clump with microwave energy; and
directing unpopped kernels displaced from said clump back to the
region of said clump while continuing to radiate said microwave
energy until a substantial portion of said kernels are popped.
2. The method of popping corn kernels in a microwave oven,
comprising the steps of:
gathering said kernels into a compact volumetric cluster;
radiating said cluster with microwave energy; and
automatically directing unpopped kernels moved from said cluster by
popping of kernels back to said cluster while continuing to radiate
said microwave energy until a substantial portion of said kernels
are popped.
3. The method of popping corn kernels in a microwave oven,
comprising the steps of:
congregating said kernels into a restricted volume bottom region of
a microwave transparent container, said kernels being supported by
said container;
radiating said container with microwave energy; and
directing unpopped kernels moved from said region by the
disturbance of at least one popping kernel automatically back into
said restricted region while continuing to radiate microwave energy
until a substantial portion of said kernels are popped.
4. The method of popping corn kernels in a microwave energy
environment, comprising the steps of:
bunching said kernels together in a microwave transparent container
wherein a substantial number of said kernels are supported at least
in part by other kernels in a bottom region of said container;
exposing said kernels to microwave energy; and
self-directing unpopped kernels displaced from said bottom region
by the popping of other kernels back to said bottom region while
continuing to expose said kernels to microwave energy until a
substantial portion of said kernels are popped.
5. The method of popping kernels using microwave energy, comprising
the steps of:
positioning said kernels in a microwave transparent container
having a closed bottom region of restricted volume wherein said
kernels are held in a compact clump to substantially reduce the
surface area of said kernels exposed from said clump from which
heat can radiate;
radiating said bottom region with microwave energy; and
directing unpopped kernels moved from said region by the popping of
other kernels back to said region by gravity while continuing to
radiate said microwave energy until a substantial portion of said
kernels are popped.
6. The method of popping corn kernels in a microwave oven,
comprising the steps of:
closely grouping said kernels together in a restricted volume
closed bottom region of a microwave transparent container wherein
said kernels define a clump;
radiating said bottom region with microwave energy; and
collecting popped kernels in an upper region of said container,
said upper region having at least one wall sloping inwardly to a
wall of said bottom region wherein unpopped kernels in said upper
region are directed back into said bottom region by gravity while
continuing to radiate said microwave energy until a substantial
portion of said kernels are popped.
7. The method of popping corn in a microwave oven, comprising the
steps of:
filling a bottom region of a microwave transparent container with a
large plurality of said kernels, said bottom region having a volume
substantially smaller than an upper region of said container
wherein said kernels are confined into a volumetric cluster defined
by a substantial number of said kernels contacting other kernels in
more than two dimensions wherein the surface area of said kernels
from which heat can be radiated away from other kernels is
reduced;
exposing said kernels to microwave energy; and
gathering popped kernels in said upper region of said container,
said upper region having a wall sloping inwardly to said bottom
region wherein unpopped kernels displaced to said upper region are
directed back to said bottom region by gravity while continuing to
expose said kernels to said microwave energy until a substantial
portion of said kernels are popped.
8. The method of popping kernels using microwave energy, comprising
the steps of:
positioning said kernels in a closed bottom microwave transparent
container having an interior surface sloping inwardly and down to
bottom region having a horizontal cross-sectional area
substantially less than the horizontal cross-sectional area of an
upper region of said container wherein said kernels congregate by
gravity into a clump in said bottom region; and
radiating said kernels with microwave energy until a substantial
portion of said kernels are popped.
9. The method of popping corn kernels by heating them with
microwave energy, comprising the steps of:
positioning said kernels in a microwave transparent container
having an interior surface inclined inwardly and down to a bottom
region of restricted volume relative to the volume of an upper
region of said container wherein said kernels congregate by gravity
into a kernel contacting volumetric cluster supported by said
container in said bottom region;
covering said container with a lid; and
radiating said kernels with microwave energy until a substantial
portion of said kernels pop by heat generated in them by absorption
of microwave energy or by heat lost by contacting kernels.
10. The method of making popcorn in a microwave oven by
substantially retaining unpopped corn kernels in a volumetric clump
during popping to maintain an approximately equal temperature among
contacting unpopped kernels and to reduce the exosed kernel surface
area from which heat can radiate outwardly from said clump,
comprising the steps of:
positioning popcorn kernels in a rigid microwave transparent
container having a generally conical interior shape with the closed
end downward wherein by gravity said kernels aggregate into a clump
supported by said container in said closed end;
covering said container with a lid that is at least partially
transparent to microwave energy; and
radiating said kernels with microwave energy in the cavity of said
oven until a substantial percentage of said kernels pop by heat
generated in said kernels by absorption of said microwave energy or
by heat lost by adjacent unpopped kernels of said clump.
11. An apparatus for popping kernels, comprising:
a microwave oven;
a microwave transparent container removably positioned in the
cavity of said oven;
said container having an interior bottom region of restricted
volume for supporting a large plurality of unpopped kernels in a
compact volumetric clump, said bottom region having a horizontal
cross-sectional area substantially less than the horizontal
cross-sectional area of an upper region of said container;
a lid for covering said container; and
said container further comprising means for directing unpopped
kernels distributed from said bottom region by the popping of at
least one other kernel back to said bottom region.
12. The apparatus recited in claim 11 wherein said container has a
substantially conical shape.
13. The apparatus recited in claim 12 wherein the sidewalls of said
conical shape extend upwardly at an angle of approximately 70
degrees.
14. An apparatus for popping kernels, comprising:
a microwave oven;
a microwave transparent container removably positioned in the
cavity of said oven, said container having a closed bottom;
a lid for covering said container; and
said container comprising means for substantially minimizing the
outward exposure area of a large plurality of kernels positioned in
said container wherein the volume of said kernels is substantially
less than the interior volume of said container, said outward
exposure area being the sum of the surface areas of the individual
kernels which face away from other kernels such that heat radiated
therefrom is not retained by other kernels.
15. An apparatus for popping kernels, comprising:
a microwave oven;
a microwave transparent container removably positioned in the
cavity of said oven;
a lid for covering said container; and
the interior shape of said container substantially minimizing the
exposure area of a large plurality of kernels positioned in the
container by congregating said kernels in a compact clump, the
volume of said clump being substantially less than the total volume
of said container, said exposure area being the outward surface
area of kernels from which heat can be radiated away from said
clump.
Description
BACKGROUND OF THE INVENTION
This invention relates to the heating of various grains, nuts or
seeds by microwave energy and has particular reference to
appliances for making popcorn or the like within a microwave
oven.
It is commonly known that heat may be applied to grains, nuts or
seeds for various purposes. Edible nuts may be roasted, rice grains
may be puffed and popcorn kernels may be popped by application of
heat either radiatively or convectively in well known conventional
ovens fueled by electrical energy, by the burning of liquid or
gaseous fuel or by combustion of solid fuel.
Popcorn has been made in many ways. Kernels have been placed in a
screenlike container with a long handle so that the container may
be held suspended above an open flame. Since the heat from the
flame usually radiates onto or contacts only one side of the supply
of kernels, it was necessary to vigorously shake the container so
that all the kernels would be heated and to prevent burning of the
popped corn. Another method was to place a supply of kernels in a
covered pan disposed on a burner of a kitchen range, for example,
and again shake the pan to properly heat all the kernels and
agitate the popped corn. Still another method has been to place the
kernels in an enclosure having wall areas containing electrical
heating elements. This method again usually requires that the
enclosure be at least slightly agitated. In all of these methods,
butter and salt must be subsequently added.
It is also known that a plurality of collapsed sealed foil-like
disposable container may be provided with a supply of kernels and
oil and agitated over a source of heat whereupon the kernels will
pop, causing the container to expand, following which the container
may be ruptured to remove the popcorn which will be at least
partially covered with the oil. In a still further known method, a
partially collapsed, sealed plastic bag of kernels, with or without
oil, is placed in a microwave oven. Microwave radiation is then
directed through the oven to the kernels, causing them to pop.
Agitation in such a case is not necessary since microwave radiation
will easily contact each kernel. A suitable oil may also be
provided in this type of device.
It has been found that butter can not be used with the packaged
systems because butter can become rancid after a period of time
such as might occur when the packages are stored or on store
shelves for a lengthy period.
SUMMARY OF THE INVENTION
The present invention overcomes the above and other disadvantages
of devices of the character described by the provision of a novel
appliance which utilizes microwave energy as the heat source. The
appliance comprises a bowl-like container of microwave-transparent
material and of selected size and shape into which seed-like items
such as popcorn kernels may be placed. Upon subjection of the
device to microwave energy, as in a microwave oven, the kernels
will become heated and will expand or explode, in the case of
popcorn kernels.
The bowl is preferably substantially conical in shape with its
small end being disposed downwardly so as to form at its lower end
an internal region of restricted volume within which the kernels
are disposed and retained in a relatively compact clump. The region
of the bowl above the area of restricted volume is larger so that
when the kernels are puffed or expanded, or exploded as in the
making of popcorn, the exploded items will be forced upwardly in
the bowl, while unexploded kernels will remain in the bottem
thereof.
The bowl may be provided with shapes other than conical, if
desired, as long as the unpopped kernels remain constantly together
in a clump at the bottom of the bowl and the popped items are
allowed to be violently propelled upwardly when heated into an area
of larger volume.
The bowl may be suitably supported so that it will be retained in
an upright position. Such support means may take any form such as a
carrousel, for example, or other attractive arrangement, or may be
simply a block of microwave-transparent material into which the
bottom of the cone is inserted. The present invention also may be
embodied in a disposable package which may be sold in stores or the
like.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other advantages of this invention will become
apparent from the following description taken in connection with
the accompanying drawings, wherein:
FIG. 1 is a vertical sectional view of a microwave oven showing a
popcorn maker embodying the invention located within the oven
cavity;
FIG. 2 is a vertical sectional view through a preferred bow and
support therefor;
FIG. 3 is an elevational view of a second bowl configuration with
support therefor;
FIG. 4 is a plan view of a bowl lid;
FIG. 5 is a vertical sectional view of a device embodying the
invention shown holding unheated kernels;
FIG. 6 is a similar view of the device of FIG. 5 showing the
invention when kernels are being heated;
FIG. 7 is an elevational view showing the invention packaged as a
carrousel;
FIG. 8 is an isometric view of a disposable popcorn maker in
packaged form; and
FIG. 9 is a vertical sectional view of the disposable popcorn maker
of FIG. 8 opened for use.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring more particularly to the drawings wherein like characters
of reference designate like parts throughout the several views,
there is shown in FIG. 1 a microwave oven 10 including an oven
cavity 12 having a popcorn maker 14 which may be positioned therein
through a door (not shown). The oven cavity is supplied with
microwave energy from a magnetron 16 via a waveguide 18. While the
magnetron 16 may generate energy of any desired frequency, a
frequency of about 2.45 KMH is particularly suitable. The oven
cavity 12 has internal dimensions which are many times the free
space wavelength of said frequency so that many different resonant
modes may be produced therein and such modes may be cyclically
distributed by a mode stirrer 20.
The cathode of magnetron 16 is supplied with filament heater power
and anode voltage power at a voltage of, for example, 4000 volts
from a high voltage power supply 22 by suitable wiring while the
anode of the magnetron 16 is ground.
It is believed that this provides sufficient description of
microwave oven 10 and for more information reference may be made to
many existing patents or to copending application Ser. No. 671,469,
filed McConnell et al and assigned to Amana Refrigeration, Inc.
It is to be understood that the present invention is concerned with
appliances which may be used for the heating of various types of
seeds, nuts, grains or the like by microwave energy. However, the
invention is primarily concerned with popcorn makers of novel
design and construction which produce relatively large fluffy
popcorn by the heating of kernels with microwave energy such as may
be supplied by a conventional household microwave oven or other
source of microwave energy.
Referring more particularly to FIG. 2, the basic popcorn maker
includes a bowl or container 24 which is of a selected shape having
a lower region of small internal volume and an upper region of
larger internal volume. Such a shape is particularly well
exemplified in the conical configuration shown in FIG. 2 wherein
the apex of the cone is located at the bottom and the larger end is
at the top. Such a conical bowl 24 may be supported by the block 26
of suitable material having a conical depression in its upper
surface in which the small end of the bowl 24 is positioned.
In a bowl 24 of the desired shape, the unpopped kernels 28 will
necessarily form a closely compacted clump in the bottom of the
bowl. When the microwave oven is operated in the normal manner, the
microwave energy will enter the oven cavity 12 and will be directed
throughout the cavity by multiple reflections off the walls of the
oven. Such energy will pass through the walls of the bowl 24 and
the microwave support block 26 and will cause heating of the
kernels, causing them to explode as is well known in the art of
making popcorn.
The bowl 24 and supporting block 26 will be made of a material
which is transparent to the microwave radiation. Glass is
particularly well suited for the invention as are several plastic
materials such as styrene, polycarbonate, and
polymethylmethacrylate, for example. Ceramic materials may also be
used if desired. It is important, however, that the bowl and block
have a low dielectric loss at microwave frequencies, thus making it
readily transparent to microwaves. However, these elements,
particularly the support block 26, may be provided with a slight
controlled amount of lossiness if desired, and this may be done by
including small amounts of metal or carbon particles. Such
lossiness should not, however, interfere with the efficient
transmission of microwaves through the material. It is particularly
desired that the bowl remain cool enough to handle after subjection
to microwave energy.
The bowl 24 will preferaby be conical in shape as shown in FIG. 2
with its side walls being angled at approximately 70.degree..
However, the bowl 30 may be shaped other than conical as shown in
FIG. 3 wherein it has a relatively small concave lower end portion
which merges into side walls which extend upwardly and outwardly to
form an upper portion of larger volume than the small end portion.
The block 32 is provided with a recess in its upper surface which
preferably conforms to the shape of the lower end portion of the
bowl 30. In both bowls 24 and 30 the extreme lower end is slightly
flattened, as shown at 33 in FIG. 2.
A lid 34 is located on the open top of the bowl to prevent
undesired escape of popcorn during a popping process. However, it
is desirable that steam which is created by the heating of the
kernels be allowed to escape. Therefore, the lid 34 is provided
with perforations 36 which may be arranged in any desired
pattern.
All parts of the device including the lid 34 are made of
microwave-transparent material such as the bowl 24 so that
microwaves may easily find their way to the clump of kernels
28.
It has been found that microwaves entering the cavity 12 progress
directly or by reflection to the clump 28 and cause the kernels in
the clump to be heated without causing any substantial heating of
the parts of the device. Such heating of the kernels or grains will
cause them to expand, puff or, in the case of popcorn, to explode.
Such explosion will cause the exploding kernels to move violently
upward in the bowl 24. It is believed that kernels near or on the
small flat bottom 33 or lying against the inclined walls of the
cone may explode before other kernels within the clump. However, in
any case, the explosion and resultant violent movement of a kernel
will cause a disruption of the kernels within the clump. The
propped kernel will fly upwardly, causing some unpopped kernels to
also be moved up in the bowl. However, such unpopped kernels wil
fall back down into the clump because of the steep inclination of
the walls and because of their relatively small size. Popped
kernels will, because of their relative size, stay above to
clump.
In FIGS. 5 and 6 there is shown a popcorn maker which is enclosed
within a chamber 38 of microwave transparent material. The popcorn
maker includes a substantially conical bowl 40 having a tube 42
extending downwardly from its small lower end to a pedestal or base
44 which supports it upon the bottom of the chamber 38. A stem 46
is located within the tube 42 and is connected at its upper end to
the under side of an apertured lid 48 which closes the top of the
bowl 40. The stem 46 is axially vertically movable in the tube 42
and the distance between these two parts is small enough to prevent
kernels from lodging therebetween. A suitable microwave-transparent
cover 50 may be located on the top of the chamber 38 if
desired.
Popcorn kernels 52 are placed in the bowl 40 by slightly raising
the lid 48 and thereafter allowing the lid to be lowered onto the
upper end of the bowl The chamber 38 containing the popper is then
placed in a microwave oven. All of the parts of the apparatus are
readily transparent to microwave energy and, therefore, microwaves
generated by the oven will contact the clump 52 of kernels in the
lower end of the bowl 40. When the kernels 52 pop or explode they
will fill up the bowl 40 and will eventually cause the lid to be
raised. Popcorn will then fall out the top of the bowl 40 to the
bottom of the chamber 38, as shown in FIG. 6.
It is to be understood that all of the parts of the device shown in
FIGS. 5 and 6 are substantially entirely nonmetallic and are
transparent to microwave energy.
Referring now to FIG. 7, there is shown a novel and attractive
packaging arrangement for the device 41 embodying the invention.
The device 14 comprising the bowl 24 with lid 34 is positioned in
the cavity 54 in a support block 25 which is suitably affixed to a
base plate or disc 56. Encircling the bowl 24 well above the base
56 is an annular canopy 58 which is supported on the base plate 56
by a number of posts 60. Each post 60 supports a replica 62 of an
animal such as a horse, for example. The upper ends of the posts
are bolted or otherwise secured to the canopy 58 and the lower ends
are preferably provided with reduced diameter end portions which
extend through the base plate into small leg members 64 by which
the entire appliance is supplied upon the bottom wall of the oven
cavity 12 or upon a glass plate located on the bottom wall as shown
at 66 in FIG. 1.
It is again to be understood that substantially the entire
appliance is easily transparent to microwave energy so that the
energy may readily contact seeds or kernels in the clump at the
bottom of the bowl 24.
The present invention can be readily applied to disposable
packaging as shown in FIGS. 8 and 9. Referring to FIG. 8, a
frusto-conical bowl 68 of collapsible material such as paper or
thin plastic is secured at its lower end to a cup-shaped portion 70
of more rigid material such as card stock or plastic. The lower and
smaller end of the cupped portion 70 is provided with a concave
paper, plastic or thin metal end cap 72. Winglike portions 74
extending from the sides of the cupped portion 70 serve to support
the device in position of use by their lower ends. A suitable
closure cap or lid 76 is sealed to and closes the upper end of the
bowl 68.
In collapsed form the device shown in FIG. 9 appears as seen in
FIG. 8 wherein the rigid portion 70 has on its upper side the bowl
68 which with closure 76, is rolled or folded downwardly thereon to
close the upper end of the rigid portion. The rigid portion 70 is
filled with popcorn kernels. This provides a neat small package
which may be readily stored.
When such a package as shown in FIG. 8 is to be used, the bowl
portion 68 is unrolled or unfolded by merely pulling on a string or
tab 78 whereupon the device will assume the shape shown in FIG. 9.
The wings or legs 74 may be bent outwardly and the device then
placed in the microwave oven in the upright position shown. Since
the kernels will be clumped together in the rigid portion 70, and
since all of the parts of the device are readily transparent to
microwave energy, the kernels will be efficiently heated and popped
to make conventional popcorn. When the popping process is completed
the closure member 76 may be easily ruptured to allow the popcorn
to be removed, after which the device may be discarded.
It is to be understood that the disposable device may take other
packaged forms as long as the final product as used comprises a
bowl having a small volume lower end portion and an upper portion
of larger volume.
From the foregoing it will be apparent that all of the objectives
of this invention have been achieved in the microwave appliance
shown and described. All parts of the device are made of material
having low dielectric loss at microwave frequencies and are,
therefore, microwave transparent and include substantially no metal
or carbons which would become heated when subjected to microwave
radiation. The presently described appliance is, as pointed out,
adaptable to various modifications and embodiments which may have
different dimensional or thermal variations.
However, it is to be understood that various modifications and
changes in the structures shown and described may be made by those
skilled in the art without departing from the spirit of the
invention as expressed in the accompanying claims. Therefore, all
matter shown and described is to be interpreted as illustrative and
not in a limiting sense.
* * * * *